The present invention relates to a workpiece processing arrangement. More particularly, it relates to a workpiece processing arrangement with the use of a laser and means for directing a laser beam toward a workpiece, as well as a radiation detector for determination of heat radiation from the heated workpiece and adjusting an intensity of the laser.
Arrangements of the above-mentioned general type are known in the art. One of such arrangements is disclosed in the German document DE-OS 2,200,696. In this arrangement an exact direct temperature measurement of a heated region of the workpiece to be processed is performed. For this purpose the arrangement is provided with a radiation detector to determine the heat radiation from the workpiece which is heated with the laser beam, and produces an output signal dependent on the intensity of the heat radiation for controlling the output of the laser beam. The zone to be processed, for example hardened, is heated by a laser beam which is oriented with a deflecting mirror onto the workpiece and has substantially a single relatively great wavelength. The intensity of the heat radiation because of the local heating of the workpiece is measured, and the output of the laser beam is controlled in dependence on the intensity of the measured heat radiation. The heating of the workpiece zone ends when the measured intensity reaches a predetermined threshold value. The laser is either switched off or the laser beam is interrupted by a cover which is arranged in the path of the beam. Thereby good results can be obtained since the workpiece surface is heated no longer and with not higher temperatures than those required for the respective processing. The radiation detector in the known arrangement is arranged so that it directly receives the heat radiation extending from the workpiece. This means that the control the outwardly located zones of a workpiece are processed which can be "seen" by the radiation detector. For processing of the inwardly located surfaces of workpieces, such as for example openings, inner threads and the like, the known arrangement is not suitable or suitably only to a lower degree, since the heat radiation is shielded from the detector by the workpiece.